The present invention relates to a sewing machine which may be used as a manually operated mechanical sewing machine for the straight stitching operation, and which may be used as an electronic sewing machine for automatically stitching various patterns by way of electronic circuits including a state electronic memory storing the pattern data.
So-called electronic sewing machine, which is provided with the static memory and electronic devices for determining the needle positions and the feeding amounts and directions per stitch in response to a signal from said static memory, has its own merits in comparison with the conventional mechanical sewing machines, that in the electronic sewing machine, so many pattern cams and other complex parts for pattern selection of the mechanical sewing machine may be replaced by small sized and compact electronic devices, and that the electronic sewing machine may attain to considerably difficult and complicated functions of high degree more easily and more neatly. On the other hand, it may be said that more than 90% of the stitching operation is directed to the straight stitching, and furthermore the merits or effects of the electronic sewing machine are hardly utilized for the straight stitching. If the simple straight stitch is to be controlled by the electronic devices, said electronic device and the relative parts must be electrically conductive in the meantime, and the electric power is considerably consumed with the increase of temperature of the parts. Besides the noise is liable to be higher than for the mechanical sewing machine. Further, since the composing elements and connections of the electric circuits are very complicated, the straight stitching operation becomes impossible if even a minor part is out of order. In view of these circumstances, the invention provides a sewing machine including the electronic devices, in which the easy straight stitching operation is performed independently from the electronic devices, but dependently on the pure mechanism.